Toner, toner stored unit, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-11256188-B2
Application number	US-201816959478-A
Country	US
Kind code	B2
Filing date	Dec 26, 2018
Priority date	Jan 18, 2018
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

Provided is a toner including toner particles, each toner particle includes: a base particle including a binder resin; and external additive particles, wherein the external additive particles include particles each having an equivalent circle diameter of 10 nm or greater, a volume average particle diameter of the particles each having an equivalent circle diameter of 10 nm or greater is 80 nm or greater but 140 nm or less, and a ratio (circumscribed circle area/particle area) of a circumscribed circle area of the particle having an equivalent circle diameter of 10 nm or greater to a particle area of the particle having an equivalent circle diameter of 10 nm or greater is 1.60 or greater but 2.60 or less.

First claim

The invention claimed is:

1. A toner, comprising:
toner particles, wherein each toner particle includes:
a base particle including a hinder resin; and
external additive particles,

wherein the external additive particles include particles each having an equivalent circle diameter of 10 nm or greater,
a volume average particle diameter of the particles each having an equivalent circle diameter of 10 nm or greater is 90 nm or greater but 130 nm or less, wherein the volume average particle diameter is calculated as a volume-weighted average of the equivalent circle diameter of the particles, and
a ratio (circumscribed circle area/particle area) of a circumscribed circle area of the particle having an equivalent circle diameter of 10 nm or greater to a particle area of the particle having an equivalent circle diameter of 10 nm or greater is 1.65 or greater hut 2.00 or less.

2. The toner according to claim 1 , wherein the particle having an equivalent circle diameter of 10 nm or greater is an aggregate.

3. The toner according to claim 1 , wherein the particle having an equivalent circle diameter of 10 nm or greater is an inorganic particle.

4. The toner according to claim 3 , wherein the inorganic particle is at least one selected from the group consisting of silica, titanium oxide, strontium titanate, and alumina.

5. The toner according to claim 4 , wherein the silica is fumed silica.

6. A toner stored unit comprising:
a unit; and
the toner according to claim 1 stored in the unit.

7. An image forming apparatus comprising:
an electrostatic latent image bearer;
an electrostatic latent image forming unit configured to form an electrostatic latent image on the electrostatic latent image bearer;
a developing unit configured to develop the electrostatic latent image formed on the electrostatic latent image bearer with a toner to form a toner image where the developing unit includes the toner;
a transferring unit configured to transfer the toner image formed on the electrostatic latent image bearer to a surface of a recording medium; and
a fixing unit configured to fix the transferred toner image onto the surface of the recording medium,
wherein the toner is the toner according to claim 1 .

8. The image forming apparatus according to claim 7 ,
wherein the image forming apparatus does not include a lubricant applying unit configured to apply a lubricant onto the electrostatic latent image bearer.

Assignees

• Ricoh Co Ltd

Inventors

• Kaneko Akihiro
• Suzuki Kazumi
• Nakajima Hisashi
• Yamauchi Yoshitaka
• Ogino Kohtaroh
• Suzuki Teruyuki
• Suzuki Namie

Classifications

• G03G9/097 Primary

  Plasticisers; Charge controlling agents · CPC title

• G03G9/09725

  Silicon-oxides; Silicates · CPC title

• G03G15/0865

  Arrangements for supplying new developer · CPC title

• G03G9/09708

  Inorganic compounds · CPC title

• G03G9/0819 Primary

  characterised by the dimensions of the particles · CPC title